GLOBAL EXTENT OF UNDETECTED GLAUCOMA

 

GUEST AUTHOR

DR. GHUNCHA KHATOON

DEPT OF COMMUNITY MEDICINE, AJMAL KHAN TIBBIYA COLLEGE, 

AMU, ALIGARH, INDIA

Undetected glaucoma is a challenging public health problem as it increases the risk of visual impairment, even in those cases where early detection could be beneficial. The loss of vision in a large population can affect the quality-of-life and socio-economic condition of the community.

The levels of undetected glaucoma globally are not clear. Reported prevalence ranges between 33% and 98%. However, a meta-analysis has shown that nearly half of all glaucoma cases are undetected world-wide. And, this number is expected to increase in the future.

Understanding these levels can spur the development of effective public health strategies and policy-level changes (e.g., screening programs) to prevent avoidable blindness.

The meta-analysis reviewed 61 articles from 55 population-based studies (n ¼ 189 359 participants; n ¼ 6949 manifest glaucoma). [1]

Variation in Undetected Glaucoma by Geographical Region:

For manifest glaucoma, the highest proportion of previously undetected cases was observed in Africa and the least in Oceania. Africa (odds ratio [OR], 12.70; 95% confidence interval [CI], 4.91e32.86) and Asia (OR, 3.41; 95% CI, 1.63e7.16) had significantly higher odds of undetected manifest glaucoma as compared with Europe.

For POAG, the highest proportion of previously undetected cases was observed in Africa and the least in North America. Africa (OR, 8.84; 95% CI, 2.64e29.62) and Asia (OR, 4.66; 95% CI, 2.07e10.51) showed significantly higher odds of undetected POAG as compared with Europe, whereas the differences between other geographical regions and Europe were statistically insignificant.

Variation in Undetected Glaucoma by Human Development Index (HDI):

Countries with low HDI had undetected cases in the proportion of 94.56% (95% CI, 92.13e96.27), compared to 70% in countries with medium to very high HDI. Countries with medium HDI (OR, 0.20;95% CI, 0.10e0.42), high HDI (OR, 0.20; 95% CI, 0.09e0.47), and very high HDI (OR, 0.12; 95% CI, 0.06e0.24) showed significantly lower odds of undetected manifest glaucoma as compared with countries of low HDI.

Variation in Undetected Glaucoma by Ethnicity:

Africans (OR, 5.55; 95% CI, 2.41e12.78) and Asians (OR, 2.62; 95% CI, 1.26e5.48) showed significantly higher odds of undetected manifest glaucoma as compared with people of European ancestry.

Projected Number of Undetected Primary Open-Angle Glaucoma Cases:

Asia alone accounts for 58.4% of all undetected POAG cases worldwide because of its sheer population size.

The number of undetected POAG cases is projected to increase by 53.2% to affect 67.06 million (95% CI, 64.11e69.59 million) people by 2040.

The largest increase will be seen in Africa (86.3%), whereas the highest number of undetected POAG cases in 2040 will remain in Asia.

Variation in Undetected Glaucoma by Asia Sub-region:

In Asia, South Asia (OR, 2.19; 95% CI, 1.01e4.77) showed significant higher odds of undetected manifest glaucoma cases as compared with East Asia, whereas the differences between the other sub-regions and East Asia were insignificant.

Variation in Undetected Glaucoma by Other Factors:

The odds of undetected POAG were lower in urban habitations (OR, 0.52; 95% CI, 0.27e0.99) as compared with rural habitation globally.

Reasons for undetected glaucoma not only include socio-economic factors and better medical facilities, but also from a complex interplay between multiple factors that include individual, community, and policy-level short-comings.

In a study performed in USA in 2014, approximately 2.4 million persons had undetected and untreated glaucoma. Overall, prevalence of both diagnosed and undiagnosed glaucoma was much higher in minorities (African-Americans and Hispanics) and the elderly. [2]

REFERENCES:

1. Soh Z, Yu M, Betzler BK, Majithia S, Thakur S, Tham YC, Wong TY, Aung T, Friedman DS, Cheng CY. The Global Extent of Undetected Glaucoma in Adults: A Systematic Review and Meta-analysis. Ophthalmology. 2021 Oct;128(10):1393-1404. doi: 10.1016/j.ophtha.2021.04.009. Epub 2021 Apr 16. PMID: 33865875.
2. Shaikh Y, Yu F, Coleman AL. Burden of undetected and untreated glaucoma in the United States. Am J Ophthalmol. 2014 Dec;158(6):1121-1129.e1. doi: 10.1016/j.ajo.2014.08.023. Epub 2014 Aug 22. PMID: 25152501.